The order was issued by a seven-judge bench led by Justice Nasir-ul-Mulk that on Monday began hearing the case related to the apex court's orders for reopening high-profile graft cases against Zardari and over 8,000 others.

The bench directed Gilani to personally appear in court to explain why contempt proceedings should not be initiated against him for deliberately disregarding the court's orders.

The bench noted that the Supreme Court had issued directions to the government several times to implement its orders regarding the reopening of graft cases.

However, the government had deliberately not acted on these orders, it contended.

The court's order is expected to lead to a fresh confrontation between the government and the judiciary at a time when the ruling Pakistan People's Party is engaged in a bruising row with the military over the memo scandal.

SC-appointed panel is also probing the memo scandal

A Supreme Court-appointed panel is also probing the memo issue and held a hearing on Monday that remained inconclusive.

The Supreme Court issued the order against the premier after the government's top law officer informed it that he had received no instructions regarding the order to reopen the corruption cases.

The court rebuked Attorney General Anwar-ul-Haq for failing to present the government's response to its orders to write to Swiss authorities to reopen cases of alleged money laundering against President Zardari.

The Attorney General earned the ire of the bench when he said he had conveyed the court's directions to the President, Prime Minister and other authorities but had received no directions from them.

Haq said the government was still considering the matter.

Justice Nasir-ul-Mulk remarked that it was not the Attorney General's job to merely convey the court's orders to the President and Prime Minister and that he should have sought directions from the authorities on writing to the Swiss government about reviving the graft cases against Zardari.

Govt has maintained Zardari immune from prosecution

The bench asked the Attorney General whether the government had anything at all to say on the issue as the court was free to issue orders in the case. The Attorney General merely repeated that he had received no directions as the government was still considering the matter.

The court briefly adjourned the hearing at about noon and asked Haq to seek directions from the government.

Though the law officer said the apex court could approach the high court to ensure the implementation of its order, the bench said such a move was not necessary at the moment.

When the hearing resumed, Haq again informed the bench that he had received no instructions from the government. The bench then issued the notice for contempt of court to Gilani.

The Supreme Court has been pressuring the Pakistan People's Party-led government to reopen the cases against the President in Switzerland since it struck down a graft amnesty that benefited Zardari and over 8,000 others in December 2009.

It has declared that the National Reconciliation Ordinance, the graft amnesty issued by former military ruler Pervez Musharraf in 2007, was unconstitutional and illegal.

Despite immense pressure from the court, the government has refused to write to Swiss authorities to reopen the cases against Zardari, saying the President enjoys constitutional immunity from prosecution.

Another bench of the Supreme Court had warned in an order issued on January 10 that Prime Minister Gilani could be disqualified if he fails to reopen the graft cases.

Gilani already under pressure of Pak army

The development comes in the backdrop of reports that the powerful Army Chief Gen Ashfaq Parvez Kayanihad told President Zardari to ask the Prime Minister clarify or retract his criticism of the Army and the Inter Services Intelligence.

Controversial Pakistani-American businessman Mansoor Ijaz, who triggered a storm in the country's political circles by making public the secret memo, has sought time till January 25 to testify before the commission.

Tensions between the government and the military reached a peak last week after Gilani said the army and intelligence chiefs had acted in an "unconstitutional and illegal" manner by filing affidavits on the memo issue in the Supreme Court without getting the government's approval.

The military rebuked Gilani, saying his remarks could have "grievous consequences". Gilani retaliated the same day by sacking Defence Secretary Lt Gen (retired) Khalid Naeem Lodhi, a confidant of Kayani, saying he had created misunderstandings over the memo issue.

The apex court accepted Kayani's request for a probe into the memo scandal while rejecting the government's contention that the issue should be investigated by a parliamentary panel.